Apparatus for assembling a multielement electron gun member

ABSTRACT

APPARATUS FOR ASSEMBLING A MULTIELEMENT ELECTRON GUN MEMBER FROM CYLINDRICAL GRID ELECTRODES. THE INCLUDED CENTRAL RODS SECURELY INSERTED INTO SUPPORT HOLES FORMED IN A SUPPORT STAND IN PRESCRIBED RELATIVE POSITIONS. THE OUTER CIRCUMFERENTIAL SURFACE OF THE CENTRAL ROD IS SHAPED SUBSTANTIALLY IN CONFORMITY WITH THE INNER CIRCUMFERENTIAL SURFACE OF EACH OF THE ELECTRON GUN UNITS, AND IS ALSO INCLINED TO SUCH AN EXTENT AS IS REQUIRED TO CAUSE ELECTRON BEAMS FROM EACH ELECTRON GUN UNIT TO CONVERGE EXACTLY AT A SINGLE POINT. OUTSIDE OF THE SUPPORT HOLES OF THE SUPPORT STAND ARE ROTATABLY PIVOTED SUPPORT ARMS WHICH ACT AS A COMPENSATION MEMBER IN LOCATING THE ELECTRON GUN UNIT BY THE CENTRAL ROD AND SUPPORT HOLE WHEN THE CYLINDRICAL GRID ELECTRODE SURROUNDING THE CENTRAL ROD IS PRESSED FROM THE SIDE.

' March 9, 1971 sm mcm SAWAGATA 3,

APPARATUS FOR ASSEMBLING MULT IELEMENT ELECTRON GUN MEMBER Filed Aug.. 9. 1968 5 Sheets-Sheet h INVENTOR.

' March 9,1971 sq-inm'cin-u SAWAAGATA 3,56

APPARATUS FOR ASSEHBLING A MULTIELEMENT ELECTRON GUN MEMBER Filed Aug. 196a 5 Sheets-$heet a March 9, 1971 SHINICHI sAwAGATA 3,568,

APPARATUS FOR ASSEMBLING A MQLTIELEMENT ELECTRON GUN MEMBER Filed Aug. 9. 1968 5 Sheets-Sheet s v FIGQ'4 March 9, m1 smcmls wAsA+A 3,568,282,

y APPARATUS FOR ASSEMBLING A MULTIELEMENT ELECTRON GUN MEMBER Filed Aug. 9 1968- 5 Sheets-Sheet 4 March 1971 SHINICHI SAWAGATA 3,56$,28,2

APPARATUS FOR ASSEMBLI NG A MULTIELEMENT ELECTRON GUN MEMBER Filed Aug. 9, 1968 Y 5 Sheets-Sheet 6 I FIG. 7

United States Patent US. Cl. 29-2519 8 Claims ABSTRACT OF THE DISCLOSURE Apparatus for assembling a multielement electron gun member from cylindrical grid electrodes. The included central rods securely inserted into support holes formed in a Support stand in prescribed relative positions. The outer circumferential surface of the central rod is shaped substantially in conformity with the inner circumferential surface of each of the electron gun units, and is also inclined to such an extent as is required to cause electron beams from each electron gun unit to converge exactly at a single point. Outside of the support holes of the support stand are rotatably pivoted support arms which act as a compensation member in locating the electron gun unit by the central rod and support hole when the cylindrical grid electrode surrounding the central rod is pressed from the side.

The present invention relates to an apparatus for assembling a multielement electron gun member, particularly a triple electron gun member most adapted for use in a shadow mask type colour television picture tube.

This type of triple electron gun member is an assembly of three electron gun units spatially positioned at a prescribed inclination. The relative positions of these electron gun units are. determined in such a manner that electron beams emitted from the three electron gun units intersect each other exactly at a single point on the shadow mask formed in a television tube. Without an exact intersection of the electron beams on the shadow mask, there would occur serious difficulties in the focus quality and colour matching to be achieved on the pickup surface of a colour television tube. For this purpose, it is required that the relative positions of the electron gun units be determined with considerable precision and that the electron gun member be assembled with such positions rigidly maintained.

Hitherto there have been proposed a variety of apparatus for assembling the aforementioned electron gun member. To date, however, it has been impossible to obtain an assembling device fully meeting the above-described requests. To give a typical example of the prior art device, there has been used, for example, a type involving a locating member. This locating member consists of an invented truncated conical body on the circumferential surface of which are formed three V-shaped grooves at a prescribed interval along the longitudinal axis of the conical body. With such assembling device, the electron gun units are first kept in the aforesaid relative positions by being inserted into the V-shaped grooves and securely held in the grooves by being pressed from the outside by a supporting means. Thereafter the electran gun units are integrally bonded together by, for example, insulating glass material to form an electron gun member with the relative positions of the electron gun units maintained as originally determined.

However, the aforementioned assembling device had the drawbacks that when the finished electron gun member "ice was removed from the truncated conical body, the assembly was unavoidably subject to a more or less deformation, so that the relative positions of the electron gun units elaborately determined by the V-shaped grooves =were dislocated with the resultant failure to exhibit an extremely accurate image. Moreover, with the above-mentioned assembling device, it was necessary to arrange cylindrical grid electrodes coaxially 'by turns in the direction of the axis of the cylinder and fix the electron gun units. Accordingly the prior art device was further handicapped by the fact that the assembling of an electron gun member involved two steps of forming the individual gun units and combining them into a gun member and that the device itself was of complicated design.

An object of the present invention is to provide an apparatus capable of assembling an electron gun member from cylindrical grid electrodes by simple operation.

Another object of the invention is to provide an apparatus capable of readily removing a finished electron gun member therefrom without any resultant undesirable external force.

In an aspect of the invention, it is intended to provide an apparatus for assembling a multielement electron gun member which comprises an apparatus for assembling a multielement electron gun member which comprises a support stand, a plurality of support holes bored in the support stand, starting with the top thereof, at a prescribed interval from each other as well as from the central axis of the support stand, central rods provided in the same number as the support holes and held thereby, said control rod consisting of an insert member to be fitted into the support hole and a supporting member for holding each electron gun unit from the inside and inclining at a prescribed angle to the central axis of the support stand, the outer circumferential surface of the supporting member having a stepwise-tapered or telescopic co-nfiguration so as to cause the cylindrical electrodes constituting the electron gun unit to be inserted in the prescribed position, the same number of rotatable support arms as the central rods having the bottom ends of the arms rotatably pivoted to the support stand so as externally to press the cylindrical electrodes held by the central rods and an encapping means provided with a device for engageably supporting the top end of each rotatable support arm.

The present invention can be more fully understood in connection with the following detailed description with reference to the appended drawings, in which:

FIG. 1 is a sectional view of an example of a triple electron gun member assembled by the apparatus of the present invention;

FIG. 2 is a sectional view of the electron gun member of FIG. 1 taken on line 22 of FIG. 1;

FIG. 3 is a perspective view of an embodiment of the apparatus according to the invention;

FIG. 4 is a section of the electron gun member of FIG. 1 actually assembled by the apparatus of FIG. 3;

FIG. 5 is a section of the open side of the base member involved in the support stand of the apparatus of FIG. 3;

FIG. 6 is an elevation of the central rod of the apparatus of FIG. 3;

FIG. 7 is a sectional view of another embodiment of the apparatus according to the invention in which there is enclosed an assembled electron gun member; and

FIG. 8 is a sectional view of the present apparatus of FIG. 7 on line 88 thereof.

Describing by reference to FIGS. 1 and 2, a triple electron gun member 10 assembled by the apparatus of the present invention comprises three electron gun units 11. Each electron gun unit has first to fourth cylindrical grid electrodes 12, 13, 14 and 15 respectively perforated in the centre with an aperture for transmitting electron beams and arranged concentrically along the central axis s-s' of the electron gun unit. The apertures of the grid electrodes are so disposed as to fall on the central axis 's-s', namely, to cause electron beams to be emitted through each electron gun unit exactly along the axis ss'. The central axes s-s' of the three electron gun units are respectively inclined at a prescribed angle to the central axis c-c' of the electron gun member so as to converge exactly at a single point on the extension thereof. The relative positions of the electron gun units are determined in such a manner that their central axes pass the apices of an equilateral triangle wherein a point P on the central axis of the electron ,gun member 10 constitutes the centroid thereof. And the central axes of the electron gun units are spaced from the central axis of the electron gun member at an equal distance R.

Support bands 16 are fused to the grid electrodes 12 to 15 in. a manner partly to surround the outer circumferential surface of each of them. The electron gun units are securely held together by causing both ends of each support band to be fused to a support rod 17 made of insulating glass thereby to bridge the grid electrodes of the adjacent electron gun units. This arrangement enables the electron gun units to be kept in the prescribed positions as described above.

There will now be described an embodiment of the I present invention by reference to the appended drawings, particularly to FIGS. 3 to 6. In the centre of the bottom surface of a triangular forked support stand 21 is formed an opening, into which is inserted a support rod 22 thereby to fix the support stand 21 in place. The axis of the support rod 22, namely, the longitudinal axis of the support stand is so set as to conform with the central axis c-c' of a triple electron gun member. Also as separately shown in FIG. 5, there are perforated three tapered holes 23 throughout the support stand 21 at equal intervals, namely, in such a manner that they fall on the periphery of a circular plane having a radius R with the central axis c-cof the electron gun member as the centre and also face the respective apices of an equilateral triangle.

In this case, the central axis of the tapered hole 23 is inclined at an angle 0 to the central axis 0-0 of the electron gun member. And the tapered circumference of the hole 23 defines an angle 6 with the central axis c-c. In this case the angle 0 is so set as to be smaller than the angle 0 In the tapered holes 23 perforated in the support stand 21 are respectively three central rods 24 as separately shown in FIG. 6. At the lower part of the central rod 24 is formed an insert member 25 correspondingly tapered to the shape of the tapered hole 23. The insert member 25 may befitted into the tapered hole 23 thereby to align the axis of the central rod 24 with the inclination angle 6 of the tapered hole 23. The base of the insert member 25 of the central rod 24 is brimmed with a flange 26. The circumferential surface of the portion 24a of the central rod extending above the flange is shaped stepwise in a tapered fashion or telescopically in line with the shape and size of the interior space of the fourth, third, second and first grid electrodes 15, 14, 13 and 12 respectively so as to permit them to be set in place in the order mentioned starting with the lower end of the central rod. The topmost end of the central rod 24 or the support member 24a is suficiently five points for insertion into a minute hole formed in the centre of the bottom wall of the first grid electrode 12. At the outer end of each forked section of the support stand 21 and outside of each tapered support hole 23 is fitted a support arm 31 which is rotatable with a stop pin as a fulcrum so as to press theelectron gun unit from the outside. This rotatable support arm 31 is intended further to determine the positions of the grid electrodes 12-1'5 held by the central rod 24 from the interior by contracting them from the outside. The side of the rotatable arm 31 which contacts the grid electrodes is so formed as to conform with the outer circumferential shape of each of them. At the outer end of the rotatable support arm 31 is embedded a stationary pin 32 in an upright position; The tapered section 33 of the stationary pin 32 is insorted into each of the tapered holes 35 of a locating encapping means 34 having a triangular three-forked shape like the support stand 21. When the encapping means is set in place by interlocking its hole means with the tapered section of the stationary pin, the top of the pin 32 extends to the top side of the forked section through the aperture perforated therein. In this position, the stationary pin is interlocking with a washer 36- and lock screw 37 thereby to fix the rotatable arm 31.

On the underside of the triangular bottom section of the aforementioned encapping means there are spatially provided three recesses in a manner to face the apices of the triangle. Each recess is so positioned as to match the first or topmost grid electrode 12 of each electron gun unit thereby to receive the top end of a compression spring 38 whose bottom end is securely fitted into a keep member 39 so as to press it to the first grid electrode 12. The outer circumferential surface of the keep mem ber 39 is so shaped as to conform with the inner circumferential surface of the first grid electrode 12. The centre of the keep member 39 is perforated with a minute aperture to match the central aperture of the first grid electrode 12 thereby to receive the fine pointed top end and the aforementioned central rod 24. In the centre of the locating encapping means 34 is disposed in an outwardly and vertically projecting relation a rod 40 for fixing the assembling apparatus. This fixing rod 40 and the support rod 22 provided in the support stand 21 cooperate in fixing the entire assembling apparatus and exactly locating the central axis of the electrode member. In the centre of the underside of the fixing rod 40 is positioned a fixing pin 41 in a manner to project toward the support stand 21, namely, into the centre of the space defined by the three electron gun units. There is also provided a hollow tapered pin 42 in a manner to slide along the circumferential surface of the central pin 41. The outer circumferential surface of this hollow pin 42 is tapered downward at the same angle as the aforementioned inclination angle 0 The downward tapered pin 42 is always pressed toward the support stand 21 by a spring 43 inserted between the encapping means 34 and the downward tapered pin 42 thereby securely to hold the grid electrodes 12 to 15 in place jointly with the rotatable arm 31.

When a triple electron gun member is to be assembled using the apparatus of the aforementioned construction, the rotatable support arms 31 are brought down to a horizontal position. And to each of the three central rods 24 inserted into the tapered holes 23 of the support stand 21 are fitted the fourth electrode 15, spacer 27, third grid electrode 14, spacer 28, second grid electrode 13, spacer 29 and first grid electrode 12 in the order mentioned, starting with the lower end of the central rod. In are exactly in line with the central axis s-s' of each electron gun unit are concentrically arranged, namely, in such a manner that the central apertures of the grid electrodes are exactly in line with the central axis S-S of each electron gun unit. The part of the bottom plate of each of the first and second grid electrodes 12 and 13 in the vicinity of the central aperture thereof is extremely thin. Consequently the aforesaid bottom plate, particularly that part around the central aperture is liable tobe deformed under an external mechanical force which will possibly be applied to the glass support rod 17 when the electron gun unit is fused thereto, with the resultant displacement of the central aperture. With the assembling apparatus of the present invention, however, such event can be fully prevented, because sidewise reinforcement by the rotatable arms 31 and the downward tapered pin 42, coupled with other support means, render the aforesaid bottom plate fully resistant to any external force occurring during the assembling operation.

After the grid electrodes 12 to 15 are set in place by inserting the central rod 24 into them, each rotatable support arm 31 is brought back to the prescribed support position by inserting the stationary pin 33 at the outer end of the rotatable support arm 31 into the tapered hole 35 of the forked section of the locating encapping means 34 thereby to set the position of the grid electrodes 12 to 15 from the outside. In this case the stationary pin 33 may be-shaped into a tapered form for insertion into the tapered hole 35 in the forked section of the locating encapping means 34. Then the stationary pin 33 inclines at an angle 0 to the central axis c-c' of the assembling apparatus, so that the outer ends of the respective stationary pins 33 present an open condition relative to said central axis c-c'. Nevertheless the locating encapping means 34 can be easily fitted.

At the same time the encapping means 34 is fitted, the outer circumferential wall of the downward tapered pin 42 tangentially contacts the outer circumferential walls of the grid electrodes, which together define the inner surface of the electron gun member, thereby to cause each electron .gun .unit to incline at an angle 0 to the central axis c-c' .of the electron gun member. At this time the keep member 39 is pressed into the first grid electrode 12 by the spring 38 so that the following grid electrode 13, 14 and 15 are similarly pressed downward by the aid of the intervening spacers 27 to 29. This enables all the grid electrodes of each electron gun unit to be aligned on the same axis which defines the prescribed inclination angle 0 with the central axis c-c of the electron gun member. As described above, the spacers 27 to 29 are disposed in the spaces between the grid electrodes 12 to 15 so as to arrange them in the prescribed positions on the central axis of each electron gun unit, thus setting up an exactly aligned triple electron gun member.

If the first or second grid electrode 12 or 13 should fall by itself toward the side of the central axis c-c' of the assembling apparatus particularly when the locating encapping means 34 is set in place, then the tapered pin 42 will drop due to the resilient force of the spring 43. and force its way through the electron gun units by its falling moment to contact the outer circumferential wall of the falling first or second grid electrode and cause the circumferential wall of said electrode to be brought in line with the inner surface of the rotatable support, arm 31. This keeps even the fine pointed part at the upper end of the central rod 24 free from any deflection, eliminates the occurrence of assembling errors, breakage of the assembled parts or other failures thereby to assure the accurate and secure alignment of the respective grid electrodes.

After arranging the grid electrodes of the triple electron gun member in the aforementioned manner, the support rod 22 and fixing rod 40 of the assembling apparatus are fitted to a glass rod fusing apparatus (not shown) thereby to fuse to the glass rod both ends of each of the support bands 16 previously welded to the grid electrodes 12 to 15, thus completing the assembly of a triple electron gun member.

To remove the finished electron gun member from the assembling apparatus, the lock screw 37 is unscrewed and the locating encapping means 34 is removed from the stationary pin 32 at the outer end of each support arm 31. Then the rotatable support arms 31 are thrown apart outward and the triple electron gun member bonded together by being fused to the glass support rod 17 is drawn out of the support stand 21. The insert member 25 of the central rod 24, as well as the tapered holes 23, are tapered at an inclination angle 0 which is designed to be larger than the inclination angle 6 of each electron gun unit, so that the central rod 24 can be easily taken out of the support stand 21 together with the three electron gun units in a body. Thus the withdrawal of the assembling apparatus can be operated without exerting any external force to the triple electron gun member. From the grid electrodes of each electron unit are pulled out the central rod 31, spacers 27 to 29, keep member 39. Then the finished triple electron gun member is taken out under a perfect condition.

As mentioned above, the present invention permits a triple electron gun member comprising grid electrodes to be completely assembled simply by a single step with accurate alignment of all parts of the member. Particularly because the three electron gun units are integrally bonded by a glass support rod, the assembling apparatus of the present invention prevents the occurrence of damage to the electrode member and assembling errors. Furthermore, since the central rod for defining the central axis of each electron gun unit is set in place by engagement with the tapered hole of the support stand having a larger taper angle than the inclination angle of each electron gun unit, the electron gun member can be easily removed from the assembling apparatus without exerting any external force to each electrode, thus substantially eliminating damage to the finished triple electron gun member as a whole. Particularly, the invention has a noticeable effect of permitting the assembly of a triple electron gun member without the necessity of acquiring any special skill and techniques.

There will now be explained another embodiment of the present invention by reference to FIGS. 7 and 8. Throughout these figures and the following description, the same parts of this embodiment as those of the preceding one are denoted by the same numerals and detailed description thereof is omitted.

In the vicinity of the central part of the triangular three-forked support stand there are perforated three vertical through holes 50, each hole facing each forked section. In the upper inside wall of the support hole 50 there is provided a narrow vertical engagement cavity 50a which opens to the top side of the support stand. The central axis of the support hole 50 is disposed parallel with the central axis c-c of the triple electron gun member at a distance of R. The support hole 50 receives the insert rod 51 of the central rod 52. At a part of the lower outer circumferential surface of the insert rod 51 is formed a narrow protuberance 51a in the lengthwise direction of the insert rod 51. Therefore when the insert rod 51 is put into the support hole 50, the narrow protuberance 51a registers with the engagement cavity 50a thereby to prevent the undesirable rotation of the insert rod 51. The approximately upper half of the insert rod 51 is inserted into the long hole 53 of the supporting member of the central rod 52 which is bored upward partly therethrough, starting with the bottom end thereof. The depth of the long hole 53 is designed to be equal to the length of the part of insert rod which is extended from the support hole. The central axis of the long hole 53 is slightly inclined to the central axis of the insert rod 51 so as to cause the central axis of the long hole 53 to define an angle 0 with the central axis 0-0 of the triple electron gun member. Of course, the magnitude of the angle 0 is determined in such a manner that when the electron gun units 11 are assembled into an electron gun member the electron beams emitted from each electron gun unit 11 converge exactly at a single point on the shadow mask of a television image pickup tube. The outer circumferential surface of the support member of the central rod is so shaped as to conform with the inner circumferential surface of the electron gun unit 11.

There will now be described the method of assembling the triple electron gun member 10 of FIGS. 1 and 2 using the apparatus according to the embodiment of FIGS. 7 and 8. Since the assembling operation of this apparatus is substantially the same as in the preceding embodiment, there will be outlined only the main particulars.

The rotatable support arms 31 are brought down to a horizontal position and the insert rods 51 are inserted into the three support holes 50 of the support stand 21 respectively. Then the upper half of each insert rod is fitted into the supporting rod 51a. At this time the central axis of the supporting rod inclines at an angle to the central axis c-c' of the electron gun member. Into the central rod 52 are inserted a fourth grid electrode 15, spacer 27, third grid electrode 14, spacer 28, second grid electrode 13, spacer 29and first grid electrode 12 in the order mentioned, starting with the bottom side of the supporting rod 51a. Each rotatable support arm 31 is brought back to the required support position shown in in the same manner as in the preceding embodiment to set up an electron gun member.

When the finished electron gun member 10 is taken out of the assembling apparatus, the rotatable support arms 31 are brought down to remove the electron gun member from the support stand 21 together with the central rods consisting of the insert rods 5-1 and supporting rods 51a. The central rods 52 fitted into the electron gun units are pulled out to release the electron gun member 10.

The embodiment of FIGS. 7 and 8 also enables the electron gun member 10 to be easily pulled out of the support stand 21 together with'the insert rods 51 without. subjecting the entire member to any deformation. Also the easy removal of the central rod 52 makes it possible to obtain anelectron gun member assembled exactly as originally aligned. This original alignment can also be carried out unfailingly with high precision due to the joint use of the support hole, central rod and bodiment permits the electron gun member to be set up at once from the grid electrodes by a simple procedure without the necessity of previously forming the individual electron gun units as was required with the prior art assembling device.

While the invention has been described in connection with some preferred embodiments thereof, the invention is not limited thereto and includes any modifications and alterations which fall within the scope of the invention as defined in the appended claims.

What I claim is:

1. Apparatus for assembling multielement electron gun member comprising:

a support stand having a central axis;

a plurality of support holes formed in the support stand, the axes of the support holes being at equal distances from the central axis of the support stand in a plane transverse to said central axis;

a plurality of central rods equal in number to the number of support holes, each central rod including an insert member adapted to be fitted into a support hole, and a support member for supporting the components of an electron gun unit, the axis of each support member, when its associated insert so other members of the assembling apparatus. This eml member is fitted into the support hole, being at a.

non-zero angle relative to the central axis of the support stand, the cross-sectional area of each support member being progressively reduced in steps to support said components of said electron gun unit thereon 'inprescribed positions; I

a plurality of rotatable support arms equal in number to the number of central rods, each support arm corresponding to a different central rod;

means pivotally mounting the end of each support arm to the support stand so that each support arm is rotatable from a free position to an operative position in which it engages the electrode components carried by its respective central rod; a d

-encapping means for clamping the supportarms in their operative positions. 2. Apparatus according to claim 1 wherein:

each said support hole has its central axis inclined at a non-zero angle relative to the centralaxis of the support stand and is tapered; each central rod is shaped so that when the insert member thereof is inserted into the support hole, the central axis of the central rod is colinear with the inclined axis of the support hole; and

the insert members of the central rods are tapered to permit insertion thereof into the tapered support holes, the taper angle of the insert members being larger than that between said central axis'of the support stand and the axis of said support holes.

3. Apparatus according to claim 1 wherein:

each said support hole has its central axis parallel with the central axis of the support stand;

the insert member and the support member of each central rod are separably joined, the insert member comprising a rod whose central axis is parallel to the axis of the support stand when it is fitted into the support hole; and i i the support member of each central rod hasa hole therein which extends from one end of the support member at a non-zero angle relative to the central axis of the support member, approximately the upper half of the insert member of a central rod being fitted into the support hole in use.

4. Apparatus according to claim 1 comprising:

a plurality of compression springs equal in number to the number of support holes; and

a corresponding plurality of keep members;

each compression spring being disposed, in use, between the encapping means and a topmost component of the individual electron gun unit on each central rod and acting on that topmost component through the keep member inserted into that topmost electrode.

5. Apparatus according to claim 1 wherein the encapping means has a pin projecting therefrom, a tapered pin being mounted on the pin and being urged away from the encapping means by a spring, the tapered pin engaging, in use, at least the topmost component of the electron gun unit supported by the central rod.

6. Apparatus according to claim 4 wherein said electrodes are cylindrical electrodes.

7. Apparatus according to claim 5 wherein said electrodes are cylindrical electrodes.

8. Apparatus according to claim 1 wherein said support member internally supports said components of an electron gun unit, said'components comprising a plurality of cylindrical electrodes.

References Cited JOHN F. CAMPBELL, Primary Examiner' R. B. LAZARUS, Assistant Examiner us. 01. XrR. 26937, ,40, 44 

